The present invention relates to semiconductor devices and electronic equipment or apparatuses using such semiconductor devices and more particularly, to a semiconductor device which operates at a very high speed and realizes a very high integration density and also to electronic equipment or apparatuses using such semiconductor devices.
Electronic equipment have been significantly advanced and remarkable progresses have been continued in recent years particularly in improving an operational speed or in achieving a higher integration. When high-speed electronic equipment is available, various sorts of processings can be realized easily and inexpensively. Further, improvement of the integration density enables realization of a sophisticated function. This tendency is remarkable, in particular, in a semiconductor device field. In this way, the improvement in the operational speed of electronic circuits, electronic equipment and semiconductor devices as well as the higher integration thereof are becoming the motive of advances and developments of the electronic industry.
A higher integration of semiconductor device increases the number of circuits to be incorporated in the device to thereby increase the number of pins of the semiconductor device necessary for connection with other devices. One of solutions to the above problem is disclosed in the specification of U.S. Pat. No. 5,216,278 which is directed to such a technique as to employ a ball grid array (BGA) package. The semiconductor device is accommodated in the BGA package to thereby form a BGA type semiconductor device.
Explanation will be made as to a prior art BGA type semiconductor device with reference to drawings.
FIG. 9 is a top view of a BGA board 1 for use in a BGA type semiconductor device. In the figure, a BGA board 1 is a wiring board which comprises a printed circuit board of organic material or ceramic. It is the semiconductor element that is mounted at a semiconductor device mounting area or position 5 in the center of the BGA board 1. Bonding pads 4 are provided on the BGA board 1 for bonding. The pads 4 and electrodes on the semiconductor element are electrically connected by bonding wires or the like. Extended substantially radially from the respective bonding pads 4 are a pattern of wires 3 which in turn are connected at their one ends with associated through holes 2. The density of the patterned wires 3 is high in the center of the BGA board 1. For the purpose of avoiding this, the through holes 2 are arranged along the outer periphery of the BGA board 1.
FIG. 10 shows a rear view of the BGA board 1. In the figure, the through holes 2 are used to interconnect the front and rear wiring lines of the BGA board 1. More in detail, on the rear side of the BGA board 1, wiring lines 6, which extend from the associated through holes 2, are connected to soldering pads 7. The pads 7 are arranged in a two-dimensional positional relation. More specifically, in the example of FIG. 10, the soldering pads in 3 rows are arranged along the four sides of the board 1 not in a single row but in a two-dimensional arrangement having a width.
FIG. 11 shows a cross-sectional view of a major part of the BGA board 1 under such a condition that a semiconductor element 8 is mounted on the BGA board 1. Electrodes on the semiconductor element 8 and the bonding pads 4 on the bonding pads 4 are connected by bonding wires 9. The wiring extends from the bonding pads 4 via the patterned wires 3, through holes 2 and wiring lines 6 to the soldering pads 7. Connected to the soldering pads 7 are solder balls 10. Though not illustrated, the BGA type semiconductor device is mounted on a printed circuit board by means of the solder balls 10 to be electrically connected to other device.
The aforementioned BGA type semiconductor device features that this type of device can have a more increased number of pins than another package such as dual in-line package (DIP) or quad flat package (QFP), under the same outer dimensions. This feature results from the fact that the soldering pads 7 shown in FIG. 10 are arranged in the 2-dimensional form which does not exist in the other packages. For this reason, even when a higher integration of semiconductor device increases the number of circuits to be incorporated therein and also the number of pins therefor, there can be realized a semiconductor device which prevents its outer dimensions from being made large in scale, which contributes to the advances and developments of the electronic industry.